MQ-501 Handheld Full-Spectrum Quantum Meter

The meter has a sample and log mode, and will record an integrated daily total in mol m-2 d-1.
Sample mode will record up to 99 manual measurements.
Log mode will power the meter on/off to make a measurement every 30 seconds.
Every 30 minutes the meter will average the sixty 30 second measurements and record the averaged value to memory.
The meter can store up to 99 averages, once full it will start to overwrite the oldest measurement with new ones.
An integrated daily total will be recorded from the 48 averaged measurements (making a 24 hr period).
Sample and log measurements can be reviewed on the LCD display or by downloading the data to a computer, however, the integrated daily total can only be viewed by downloading the data to a computer.
Downloading data to a computer requires the AC-100 communication cable (a standard USB cable will not work) and ApogeeAMS software.
Unit comes with a free protective carrying case.

Calibration Uncertainty ± 5 %

Measurement Range 0 to 4000 µmol mˉ² sˉ¹

Measurement Repeatability Less than 0.5 %

Long-term Drift (Non-stability)Less than 2 % per year

Non-linearity Less than 1 % (up to 4000 µmol mˉ² sˉ¹)

Response Time Less than 1 ms

Field of View 180˚

Spectral Range389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)

Directional (Cosine) Response ± 5 % at 75˚ zenith angle

Azimuth Error Less than 0.5 %

Tilt Error Less than 0.5 %

Temperature Response -0.11 ± 0.03 % per C

Uncertainty in Daily TotalLess than 5 %

Detector Blue-enhance silicon photodiode

Housing Anodized aluminum body with acrylic diffuser

IP Rating IP68

Operating Environment0 to 50 C; less than 90 % non-condensing relative humidity up to 30 C; less than 70 % non-condensing relative humidity from 30 to 50 C; separate sensors can be submerged in water up to depth of 30 m

Meter Dimensions 126 mm length, 70 mm width, 24 mm height

Sensor Dimensions 24 mm diameter, 37 mm height

Mass 180 g

Cable Approximately 0.17 m of shielded, twisted-pair wire with TPR jacket (high water resistance, high UV stability, flexibility in cold conditions)

Typical applications include PPFD measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments.